Fix BFT Time link

Author: webmaster128

packages/std/src/types.rs

@@ -31,7 +31,7 @@ pub struct BlockInfo {
     pub height: u64,
     /// Absolute time of the block creation in seconds since the UNIX epoch (00:00:00 on 1970-01-01 UTC).
     ///
-    /// The source of this is the [BFT Time in Tendermint](https://docs.tendermint.com/master/spec/consensus/bft-time.html),
+    /// The source of this is the [BFT Time in Tendermint](https://github.com/tendermint/tendermint/blob/58dc1726/spec/consensus/bft-time.md),
     /// which has the same nanosecond precision as the `Timestamp` type.
     ///
     /// # Examples